\newcommand{\thetak}{\theta\mathbf{\hat{k}}}

\newcommand{\robax}[2]{{}^{#1}{#2}}

\newcommand{\robabx}[3]{{}^{#1}{#3}_{#2}}

\newcommand{\robabcx}[4]{{#4}^{#1}_{{#2},{#3}}}

\newcommand{\robabcdx}[5]{{}^{#1}_{#2}{#5}^{#3}_{#4}}
